Why are people more likely to kill themselves in the spring and summer?

Beloved purse designer Kate Spade died by suicide Tuesday, sending shock waves through the fashion world and beyond. Just days later, another prominent figure, chef Anthony Bourdain, was found dead of an apparent suicide on Friday morning.

Their deaths are shocking for so many reasons — not only because they appeared to be living happy lives but also because it fell at the start of summer, when warmer weather is expected to put an end to weather-related mood instabilities such as seasonal affective disorder. While it’s not possible to confirm that the designer was suffering from depression at this point, we do know that her death falls directly during the time period when suicides are — surprisingly — highest in America: spring and summer.

Kate Spade (Photo: AP)

Why do these sun-soaked seasons bring the highest rates of suicide? Here’s what you need to know.

The idea that suicide is highest during the holidays is a myth.

Although many people imagine that rates of suicide are highest in colder months, statistics show that’s not accurate. According to a 2015 report from the Centers for Disease Control and Prevention (the most recent year for which data is available), November and December showed the lowest rates of suicide in the U.S., with an average of 111 suicides per day. The number — as it has in years past — jumped beginning in March, with a peak in May, when there were nearly 128 suicides per day.

The concept is nothing new — but researchers still don’t know the reason.

The phenomenon of a spike in suicides during the nicer months of the year is not new. According to a Live Science report, researchers have been noticing spikes in spring and summer suicides since the 1800s. An American researcher from the University of West Florida, Scott Bridges, published one of the earliest comprehensive reports on this in 2005, with data as far back as the 1970s.

An increase in sunlight and warm weather could be to blame.

While it may seem counterintuitive, warmer weather may actually be one of the causes. For those suffering from clinical depression, some researchers have found, spring and summer may bring suicidal thoughts to the surface. One expert in Britain, where the same trend occurs, captured it well for the Guardian: “It is a harsh irony that the partial remission, which most depression sufferers experience in the spring, often provides the boost of energy required for executing a suicide plan.”

A spike in allergies may also contribute.

Another convincing explanation for the increase in suicides during the warm months could be the rise in allergies that tends to accompany this time of year. Researchers have found that increased pollen counts can set off an “inflammatory chain reaction” in people with allergies that triggers the release of chemicals that cause anxiety and stress. A study from the journal BMJ by two European researchers and an American supported this hypothesis, finding that this reaction is most harmful for those with existing mood disorders.

There are many other theories about why these months see a spike in suicides.

Although increased energy and high pollen counts are two of the leading theories for why this time of year produces more suicides, they are far from the only ones. Researchers have explored many other possibilities (none of them with conclusive evidence), including air pollution, seasonal peaks in bipolar disorder, and the increase in social interactions in warmer months (which can add stress).

Despite this, the myth that suicides are highest in the winter months prevails.

The Annenberg Public Policy Center (APPC) at the University of Pennsylvania has been tracking how the media covers what they call the winter “suicide myth” since 1999. In all but two of those years, the majority of news articles have focused on winter months — thereby, according to APPC, spreading misinformation.

“It actually doesn’t help those who may be experiencing suicidal thoughts to tell them that [winter] is the time of year that others are taking their lives,” said Dan Romer, director of research at APPC. “Research has shown that this kind of information can be harmful.”

While suicide risks are higher in the spring and summer, it is still rare for someone with a mental illness to take his or her own life.

Perhaps the most important thing to note about the seasonal spike in suicides is that warm weather doesn’t mean that people with mental illness will suddenly think about ending their lives. On top of the fact that there are other underlying causes of suicide, not everyone with a mental illness contemplates (or attempts) suicide. With proper treatment, mental illness can be managed safely and effectively, dramatically reducing an individual’s risk of suicide.